1. Field
The present disclosure relates generally to aircraft and, in particular, to operating aircraft. Still more particularly, the present disclosure relates to a method and apparatus for displaying positions of an aircraft from positioning systems for the aircraft.
2. Background
In an aircraft, a flight management system provides assistance with a number of different in-flight tasks. As a result, workload and flight crew may be reduced. For example, a flight management system manages the flight plan during flight of the aircraft. The flight management system receives position information input from different sensors to identify the position of the aircraft. With the position of the aircraft, the flight management system may guide the aircraft along the flight plan. The information managed by the flight management system may be displayed on control display unit (CDU), a multifunction display (MFD), a navigation display (ND), or other display devices for the flight management system.
One function of the flight management system is to identify a position of the aircraft and the accuracy of the position identified for the aircraft. A flight management system often uses many sensors to identify the position of the aircraft. For example, a localizer receiver, a global positioning system receiver, a VHF omnidirectional range (VOR) device, distance measuring equipment (DME), an inertial reference system (IRS), and other suitable devices may be used. This position may be used to manage the navigation of the aircraft along the route identified in the flight plan.
Each of the sensors provides information about the position of the aircraft. The flight management system combines the positions from the sensors to identify the position of the aircraft. This position may be referred to as a system position for the aircraft as generated by the flight management system from the positions indicated by the different sensors.
In some instances, one of the sensors may not identify a position of the aircraft as accurately as desired. In this situation, the pilot may analyze the information generated by the sensors to identify whether one or more of the sensors are not providing a position of the aircraft with a desired level of accuracy. When the sensors are identified as not providing a desired level of accuracy, the pilot may remove that sensor from use. As a result, the remaining sensors generating positions for the aircraft may provide a desired level of accuracy.
This process of identifying a sensor that does not provide a desired level accuracy may require more time and effort than desired. Currently, a pilot interacts with the flight management system through a control display unit. The control display unit currently shows information from sensors. For example, the pilot can configure the flight management system to display the latitude and longitude computed for the aircraft using the sensors. The information, however, is displayed as text. The text may be alphanumeric.                The pilot reads this information and performs calculations to identify which sensor is working as desired. This process may take more time and effort than desired with the other tasks that the pilot performs during operation of the aircraft. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.        